The present invention relates to a blood sampling device that incorporates a lancet for piercing the skin.
Various types of blood sampling devices for drawing a blood sample from a skin puncture made by a lancet have been described. For example, U.S. Pat. No. 4,517,978 to Levin, et al. discloses a blood sampling device which is provided with a housing, a lancet holder having a lancet with a sharp point, a lancet assembly supported by the lancet holder, and an actuator mechanism for moving the lancet holder from a cocked position to a puncture position and back to an intermediate position between the cocked and puncture positions. Movement of the lancet holder is controlled by a pair of opposed springs, one of which drives the lancet holder from the cocked position to the puncture position and another of which draws the lancet holder from the puncture position to the intermediate position.
One problem with conventional spring-loaded blood sampling devices is the tendency of the lancet holder to oscillate after a puncture is made due to the use of one or more springs for driving the lancet holder. If of a sufficient magnitude, such oscillation could cause, for example, a second puncture to be made after the initial puncture, resulting in unnecessary pain.
A blood sampling device of the type described above is typically used with an industry-standard lancet assembly having a generally cylindrical plastic body, a lancet with a sharp tip and which is supported by the plastic body, and a plastic protective cap attached to the body that covers the tip of the lancet to prevent inadvertent skin puncture prior to use of the blood sampling device. A conventional lancet assembly is shown, for example, in FIG. 6 of U.S. Pat. No. 4,976,724 to Nieto, et al.